I brought the complete package of ATC 3 a couple of days ago and am flying Xplane 12.  I have everything set up nicely to a point.  I can connect, upload my simbrief plan, I am using Copilot initially to do the radios and I can get clearance, pushback and taxi clearance no problem.  However, when I get to holding short at the assigned runway, the radio moves to the tower and instantly moves back to the ground.  I have tried to have copilot run the radio and I have manually tried to do it with the same results.  I have tried two departure airports. Once out of DFW and Once out of SNA. Even after I take off without clearance, I can not get the radio to switch departure frequencies etc.  Anyone had this issue?  Any help would be greatly appreciated. Everything looks great about the program outside, not being able to switch the COM frequencies. 

Thank you!

Sounds like X-Plane is trying to control your radios.

XP 12 has an option to have X-Plane set all radio frequencies.  If that option is checked, P2A will not be able to change frequencies at all, unless it tries to change to the X-Plane assigned frequency.  You have to uncheck the box "Auto-tune recommended frequencies".
In the XP menu, select the icon of the headset.
Then, in the speech dialog that opens, click the headset.
Uncheck both checkboxes at the bottom.
 

Dave